Power transmission



FIG.

II D Q 19 Dec. 14, 1965 w. w. TOY 3, 7

POWER TRANSMISSION Filed Sept. 50, 1963 s Sheets-Sheet 1 INVENTOR.

WILLIAM W. TOY

d' 6,314 KWXM A T TOR/VEYS Dec. 14, 1965 w. w. TOY 3,223,047

POWER TRANSMISSION Filed Sept. 30, 1963 3 Sheets-Sheet 2 H. E. Q

V REL Ll ZNVENTOR.

WILLIAM W. TOY

3| WlTTOR/VEYS Dec. 14, 1965 w. w. TOY

POWER TRANSMISSION 3 Sheets-Sheet 3 Filed Sept. 50, 1965 m h 6 M An V wa a a a a a m B I w B .W. C I a \w xV/ x M. m w u m m m m m ,INVENTOR.

WILLIAM W. TOY

ATTORNEYS United States Patent Oflice 3,223,047 l atented Dec. 14, 19653,223,047 POWER TRANSIVHSSION William W. Toy, Bloomfield Hills, Micl1.,assignor to Sperry Rand Corporation, a corporation of Delaware FiledSept. 30, 1963, Ser. No. 312,681 6 Claims. (Cl. 103162) This inventionrelates to power transmissions and particularly to high-speed pressureenergy translating devices of the rotary type which are used as variabledisplacement pumps.

Such rotary fluid pressure energy translating devices comprise arotatably mounted drive member, a plurality of cylinders, pistonsreciprocable in the cylinders, and motion-converting meansinterconnecting the pistons and the drive member. An inlet and an outletcommunicate successively with one of the end of each cylinder through avalve plate in contact with the cylinder, which valve plate has an inletopening and an outlet opening. When such a device is operated as a pumpby rotating the drive member, the motion-converting means changes therotation of the drive member into reciprocating motion of the pistons topump fluid from the inlet to the outlet.

In such devices, the valve plate is rotated to vary the displacementand, in turn, the output of the device by changing the relationship ofthe inlet and outlet openings to the top and bottom of the shapes of thepistons. A major problem in such devices is that as the valve plate isrotated from a full flow to a zero flow condition, the rotation of theparts without fluid flow causes excessive heating of the device.

It is an object of this invention to provide such a pressure energytranslating device of the variable displacement type wherein optimumtemperature stabilization is obtained during partial and Zero outletflow conditions.

In the drawings:

FIG. 1 is a part sectional view of a device embodying the invention.

FIG. 2 is a sectional View taken along the line 22 of FIG. 1.

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 1.

FIG. 4 is a sectional view taken along the line 44 in FIG. 1.

FIG. 5 is a sectional view taken along the line 55 in FIG. 1.

FIGS. 6, 7 and 8 are diagrammatic views showing the manner in which theinvention achieves its intended purpose.

Referring to FIG. 1, the invention relates to a rotary fluid pressureenergy translating device 10 which comprises a housing 11 and arotatable cylinder block 12 having a plurality of cylinders 13 in whichpistons 14 are reciprocably mounted. Connecting rods 15 are universallypivoted to pistons 14 at one end and are connected at the end thereof todrive member 16 by universal joint 17. The drive member 16 is fixed to adrive member 18. A double cardan universal joint 19 extends between thedrive member and cylinder block 12 so as to maintain them in properangular alignment.

The cylinder block 12 engages a valve plate 20 that is provided with apair of openings 21, 22 that are successively brought into communicationwith the ends of the cylinders 13. To operate such a pressure energytranslating device 10 as a pump, the drive member 18 is rotated by amotor M and the openings 21, 22 are connected, respectively, to a sourceof liquid and a device which is to be supplied with liquid, such as amotor. Rotation of drive member 18 causes pistons 14 to reciprocate, andfluid is drawn through inlet opening 21 and forced out of outlet opening22. By rotating the valve plate 20 in any conventional manner, such asutilization of gear 22 and rack 23 or the like, the relative positionsof the inlet opening 21 and outlet opening 22 to the bottom of thestroke of the pistons is changed so that the displacement and resultantoutput of the device is changed, in accordance with well-known practice.

According to the invention, a substantially radial axially extendingwall or dam 25 is provided in the inlet opening 21 of valve plate 20,thereby dividing the inlet opening into a main inlet opening 21a and asecondary inlet opening 21b. In addition, valve plate 20 of the deviceis provided with an arcuate diversionary passage 26 in the area betweenthe inlet and outlet. Passage 26 registers with a groove 27 in the faceof valve block 24. A passage 28 extends from groove 27 to the exterior.This passage is connected by line L to a heat exchanger 29 and then tothe fluid reservoir 31.

The manner in which the invention achieves the intended purpose can bebest understood by referring to FIGS. 68, which are views of acylindrical section in which the relationship of the valve plate andcylinders is shown in two dimensions.

With the unit at its full flow orientation, as shown in FIG. 6, fluid isdrawn in the inlet passage throughout the main passage 21a and secondarypassage 21b of the valve plate and exhausted throughout its entireoutlet opening 22. Fluid is allowed to pass freely about the diversiondam 25.

With the unit at its partial flow orientation, as shown in FIG. 7, thevalve plate 20 is displaced with respect to the bottom dead-centerposition of the pistons and valve block, permitting part of the exhauststroke to occur in the inlet 21 of the valve plate 20. A portion of thefluid is pumped into the confined dam area or secondary inlet opening21b, initiating a flow through the groove 27 and passage 28 to thereservoir 31.

With the unit at its nearly zero or zero flow orientation, as shown inFIG. 8, the valve plate 20 is further displaced with respect to thebottom dead-center position of the pistons and valve block, approachinga zero flow net in both inlet and outlet openings 21, 22 of the valveplate. However, the piston orientation causes a high pressure zonewithin an inlet opening 21b, permitting a flow of fluid to the reservoirand replacement of this same volume with fresh fluid from the primaryinlet opening 21a.

It is significant that the fluid leaving the unit A is a mixture of theinlet fluid B and the high pressure fluid C that is carried into the lowpressure chamber. A means has therefore been provided to expose portionsof the cooling flow (the flow entering at B and leaving at A) to thesurface of the cylinder walls throughout the entire length of thecylinder above the pistons on both the high and low pressure sides. Bothvalve plate leakage at surfaces D and E and piston leakage enter orleave the cavities through which the cooling flow circulates. It is thiscomplete circulation of the cooling flow through both the high and lowpressure cavities, where it is also exposed to leakage, that lowers thetemperature gradients within the unit.

The invention described above has the following fundamental advantagesso far as providing cooling flow is concerned:

(A) A positive pressure cooling flow is provided without throttling thefluid pumped for cooling from the high pressure side of the pump.

(B) The cooling flow available increases as the unit is stroked towardcut-ofl.

(C) The volumetric capacity of the pump is unchanged when thisarrangement for cooling is used.

(D) The pressure and flow characteristics of the cooling fluid as theunit is stroked back can be chosen by placement and sizing of thediversion dam 25. This design choice is independent of overallpumpcharacteristics so far as operating pressure and flow are concerned.

(E) The expense of adding this feature to a fixed angle variable pump ofthe type shown is nominal. The change requires only the addition of thediversion dam and the additional passages 2628 for carrying away thecooling fluid.

I claim: 1. In a hydraulic system, the combination comprising a housing,a rotary fluid pressure energy translating device on said housing, saiddevice being of the type having a rotatable drive member, a cylinderblock rotatably mounted in said housing and having a plurality ofaxially positioned cylinders, pistons reciprocable in said cylinders,and motion-converting means interconnecting the reciprocating pistons tothe rotatable drive member, a valve plate associated with one end ofsaid cylinder block, said valve plate having an inlet and an outletwhich alternately communicates with the cylinders in said block as saidblock rotates, and a dividing Wall interposed in said inlet andextending generally axially thereof to divide said inlet into a maininlet opening and a secondary inlet opening, said valve plate beingrotatable to vary the displacement of said device, and a diversionarypassage associated with said secondary inlet opening and adapted toregister progressively therewith as the valve plate is rotated from afull-flow condition to a zero-flow condition. 2. In a hydraulic system,the combination comprising a housing, a rotary fluid pressure energytranslating device on said housing, said device being of the type havinga rotatable drive member, a cylinder block rotatably mounted in saidhousing and having a plurality of axially positioned cylinders, pistonsreciprocable in said cylinders, and motion-converting meansinterconnecting the reciprocating pistons to the rotatable drive member,a valve plate associated with one end of said cylinder block, said valveplate having a substantially identical inlet and outlet whichalternately communicates with the cylinders in said block as said blockrotates. and a dividing wall interposed in said inlet and extendinggenerally axially thereof to divide said inlet into a main inlet openingand a secondary inlet opening, said valve plate being rotatable to varythe displacement of said device, and a diversionary passage associatedwith said secondary inlet opening and adapted to register progressivelytherewith as the valve plate is rotated from a full-flow condition to azero-flow condition.

3. In a hydraulic system, the combination comprising a housing,

a rotary fluid pressure energy translating device in said housing,

said device being of the type having a rotatable drive member,

a cylinder block rotatably mounted in said housing and having aplurality of axially positioned cylinders,

pistons reciprocable in said cylinders,

and motion converting means interconnecting the reciprocating pistons tothe rotatable drive member,

a valve plate associated with one end of said cylinder block,

said valve plate having an inlet and an outlet which alternatelycommunicates with the cylinders in said block as said block rotates,

and a dividing wall interposed in said inlet and extending generallyaxially thereof to divide said inlet into a main inlet opening and asecondary inlet opening,

said valve plate being rotatable to vary the displacement of saiddevice,

and an arcuate groove in said housing of lesser radial width than saidinlet and outlet adapted to overlap progressively the secondary inletopening of the inlet as the valve plate is removed from a full open to ano-flow position,

said groove communicating with a zone of lesser pressure than the inletpressures.

4. In a hydraulic system, the combination comprising a housing,

a rotary fluid pressure energy translating device in said housing,

said device being of the type having a rotatable drive member,

a cylinder block rotatably mounted in said housing and having aplurality of axially positioned cylinders,

pistons reciprocable in said cylinders,

and motion-converting means interconnecting the reciprocating pistons tothe rotatable drive member,

a valve plate associated with one end of said cylinder block,

said valve plate having an inlet and an outlet which alternatelycommunicates with the cylinders in said block as said block rotates,

and a dividing wall interposed in said inlet and extending generallyaxially thereof to divide said inlet into a main inlet opening and asecondary inlet opening,

said valve plate being rotatable to vary the displacement of saiddevice,

and a diversionary passage associated with said secondary inlet openingand adapted to register progressively therewith as the valve plate isrotated from a full-flow condition to a zero-flow condition,

said diversionary passage being in communication with a fluid reservoir.

5. In a hydraulic system, the combination comprising a housing,

a rotary fluid pressure energy translating device in said housing,

said device being of the type having a rotatable drive member,

a cylinder block rotatably mounted in said housing and having aplurality of axially positioned cylinders,

pistons reciprocable in said cylinders,

and motion-converting means interconnecting the reciprocating pistons tothe rotatable drive member,

a valve plate associated with one end of said cylinder block,

said valve plate having an inlet and an outlet which alternatelycommunicates with the cylinders in said block as said block rotates,

and a dividing wall interposed in said inlet and extending generallyaxially thereof to divide said inlet into a main inlet opening and asecondary inlet OPBIlll'lg,

said valve plate being rotatable to vary the displacement of saiddevice,

and a diversionary passage associated with said secondary inlet openingand adapted to register progressively therewith as the valve plate isrotated from a full-flow condition to a zero-flow condition,

said diversionary passage communicating with a reservoir.

6. In a hydraulic system, the combination comprising a housing,

a rotary fluid pressure energy translating device in said housing,

said device being of the type having a rotatable drive member,

a cylinder block rotatably mounted in said housing and having aplurality of axially positioned cylinders,

pistons reciprocable in said cylinders,

and motion-converting means interconnecting the reciprocating pistons tothe rotatable drive member,

a valve plate associated With one end of said cylinder block,

said valve plate having an inlet and an outlet which alternatelycommunicates with the cylinders in said block as said block rotates,

and a dividing wall interposed in said inlet and extending generallyaxially thereof to divide said inlet and an arcuate groove in saidhousing of lesser radial Width than said inlet and outlet adapted tooverlap progressively the secondary inlet opening of the inlet as thevalve plate is moved from a full open to 5 no-flow position,

said groove communicating with a zone of lesser pressure than inletpressure.

References Cited by the Examiner UNITED STATES PATENTS 2,117,512 5/1938Scott 10341 X 2,524,235 10/1950 Schenk 103-41 X 3,108,542 10/1963Badenoch et al. 103162 into a main inlet opening and a secondary inlet15 opening, said valve plate being rotatable to vary the displacement ofsaid device,

DONLEY J. STOCKING, Primary Examiner.

LAURENCE V. EFNER, Examiner.

1. IN A HYDRAULIC SYSTEM, THE COMBINATION COMPRISING A HOUSING, A ROTARYFLUID PRESSURE ENERGY TRANSLATING DEVICE ON SAID HOUSING, SAID DEVICEBEING OF THE TYPE HAVING A ROTATABLE DRIVE MEMBER, A CYLINDER BLOCKROTATABLY MOUNTED IN SAID HOUSING AND HAVING A PLURALITY OF AXIALLYPOSITIONED CYLINDERS, PISTONS RECIPROCABLE IN SAID CYLINDERS, ANDMOTION-CONVERTING MEANS INTERCONNECTING THE RECIPROCATING PISTONS TO THEROTATABLE DRIVE MEMBER, A VALVE PLATE ASSOCIATED WITH ONE END OF SAIDCYLINDER BLOCK, SAID VALVE PLATE HAVING AN INLET AND AN OUTLET WHICHALTERNATELY COMMUNICATES WITH THE CYLINDERS IN SAID BLOCK AS SAID BLOCKROTATES, AND A DIVIDING WALL INTERPOSED IN SAID INLET AND EX-